//===================================================================================
// Microsoft patterns & practices
// Composite Application Guidance for Windows Presentation Foundation and Silverlight
//===================================================================================
// Copyright (c) Microsoft Corporation.  All rights reserved.
// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY
// OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT
// LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
// FITNESS FOR A PARTICULAR PURPOSE.
//===================================================================================
// The example companies, organizations, products, domain names,
// e-mail addresses, logos, people, places, and events depicted
// herein are fictitious.  No association with any real company,
// organization, product, domain name, email address, logo, person,
// places, or events is intended or should be inferred.
//===================================================================================
using System;
using System.Collections.Specialized;
using System.Linq;
using Microsoft.Practices.Prism.Properties;
using Windows.UI.Xaml.Controls;

namespace Microsoft.Practices.Prism.Regions
{
	/// <summary>
	/// Adapter that creates a new <see cref="SingleActiveRegion"/> and monitors its
	/// active view to set it on the adapted <see cref="ContentControl"/>. 
	/// </summary>
	public class ContentControlRegionAdapter : RegionAdapterBase<ContentControl>
	{
		/// <summary>
		/// Initializes a new instance of <see cref="ContentControlRegionAdapter"/>.
		/// </summary>
		/// <param name="regionBehaviorFactory">The factory used to create the region behaviors to attach to the created regions.</param>
		public ContentControlRegionAdapter(IRegionBehaviorFactory regionBehaviorFactory)
			: base(regionBehaviorFactory)
		{
		}

		/// <summary>
		/// Adapts a <see cref="ContentControl"/> to an <see cref="IRegion"/>.
		/// </summary>
		/// <param name="region">The new region being used.</param>
		/// <param name="regionTarget">The object to adapt.</param>
		protected override void Adapt(IRegion region, ContentControl regionTarget)
		{
			if (regionTarget == null) throw new ArgumentNullException("regionTarget");
			bool contentIsSet = regionTarget.Content != null;
			//			contentIsSet = contentIsSet || (BindingOperations.GetBinding(regionTarget, ContentControl.ContentProperty) != null);
			if (contentIsSet)
			{
				throw new InvalidOperationException(Resources.ContentControlHasContentException);
			}

			region.ActiveViews.CollectionChanged += delegate
			{
				regionTarget.Content = region.ActiveViews.FirstOrDefault();
			};

			region.Views.CollectionChanged +=
				(sender, e) =>
				{
					if (e.Action == NotifyCollectionChangedAction.Add && region.ActiveViews.Count() == 0)
					{
						region.Activate(e.NewItems[0]);
					}
				};
		}

		/// <summary>
		/// Creates a new instance of <see cref="SingleActiveRegion"/>.
		/// </summary>
		/// <returns>A new instance of <see cref="SingleActiveRegion"/>.</returns>
		protected override IRegion CreateRegion()
		{
			return new SingleActiveRegion();
		}
	}
}